Apparatus for advancing strands



Sept. 6, 1955 v. A. RAYBURN APPARATUS FOR ADVANCING STRANDS Filed July 8, 1954 7 Sheets-Sheet l INVENTOR. V. A. RA YBURN ATTORNEY vs Ill. 1 l:

Sept. 6, 1955 v. A. RAYBURN APPARATUS FOR ADVANCING STRANDS 7 Sheets-Sheet 2- Filed July 8, 1954 INVENTOR V A. RA YBURN ATTORNEY Sept. 6, 1955 v. A. RAYBURN APPARATUS FOR ADVANCING STRANDS 7 Sheets-Sheet 3 Filed July 8, 1954 INVENTOR.

L A. RA YBURN ATTORNE Sept. 6, 1955 v. A. RAYBURN APPARATUS FOR ADVANCING STRANDS 7 Sheets-Sheet 4 Filed July 8, 1954 Rb 0k Mb INVENTOR. L A. RA YBURN ATTORNEY Sept. 6, 1955 v. A. RAYBURN APPARATUS FOR ADVANCING STRANDS 7 Sheets-Sheet 5 Filed July 8, 1954 AHIYJF Ill]! INVENTORQ L A. RA VBURA/ Sept. 6, 1955 v. A. RAYBURN APPARATUS FOR ADVANCING STRANDS 7 Sheets-Sheet 6 Filed July 8, I954 III III 45 INVENTOR.

L A. RA YBUR/V A TTORNEY Sept. 6, 1955 v. A. RAYBURN APPARATUS FOR ADVANCING STRANDS 7 Sheets-Sheet 7 Filed July 8, 1954 8 6 l 5 7 6 I B 5 IN V EN TOR. l/ A. RA YBURN A Tl'ORNEY FIG, I2

United States Patent APPARATUS FOR ADVANCING STRANDS Vincent A. Rayburn, Baltimore, Md., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application July 8, 1954, Serial No. 442,015

12 Claims. (Cl. 242-45) This invention relates to apparatus for advancing strands, and more particularly to apparatus for advancing simultaneously a plurality of strands individually at a constant linear speed and under substantially constant and equal tensions.

This application is a continuation-in-part of my copending applications, Serial No. 238,546, filed July 25, 1951, and Serial No. 289,459, filed May 23, 1952.

In the electrolytic production of copper-covered, steel core strands, it is desirable to advance simultaneously and continuously a plurality of steel strands through electroforming apparatus designed to deposit a heavy covering of copper electrolytically on the strands as they advance therethrcugh. Essential to a uniform product is the requirement that all of the strands advance through the electroforming apparatus at the same predetermined, constant, linear speed. Further, it is essential thatsubstantially equal and constant tensions be maintained in the strands throughout the electroforming apparatus to insure positive electrical contact between the strands and the contact roller. In addition, it is desirable to provide means for adjusting simultaneously the tensions in the strands without affecting the predetermined linear speed thereof or to change the speed of all the strands without affecting the predetermined tensions thereof.

An object of this invention is to provide new and improved apparatus for advancing strands.

Another object of this invention is to provide new and improved apparatus for advancing simultaneously a plurality of strands individually at a constant linear speed and under substantially constant and equal tensions.

Strand advancing apparatus embodying certain features of the invention may include a strand-metering and holdback means for withdrawing a strand from its supply and letting it out at a predetermined constant linear speed, and a strand-tensioning capstan for pulling the strand against the drag created by the strand-metering and holdback means with a force tending to advance the strand faster than the predetermined linear speed. The capstan is designed to yield rotationally whenever the torque applied thereto resulting from the frictional drag exerted by the strand on the capstan exceeds a predetermined value.

The above-described and other objects and features of the invention will be apparent from the following description of specific embodiments thereof, when read in conjunction with the accompanying drawings, in which:

Fig. l is a schematic side elevation of the left end portion of a strand-advancing apparatus embodying the invention associated with electroforming apparatus;

Fig. 2 is a schematic side elevation of the right end portion of the strand-advancing apparatus;

Fig. 3 is a top plan view of the portion of the strandadvancing apparatus shown in Fig. 1.

Fig. 4 is a top plan view of the portion of the strandadvancing apparatus shown in Fig. 2.

Fig. 5 is an enlarged vertical section taken along line 5-5 of Fig. l with parts thereof broken away for clarity;

. Fig. 1;

Fig. 6 is an enlarged, fragmentary portion of the apparatus shown in Fig. 5;

Fig. 7 is a vertical section taken along line 7-7 Fig. 8 is an enlarged, fragmentary, vertical section taken along line 8-8 of Fig. 2 with parts thereof broken away for clarity;

Fig. 9 is a vertical section taken along line 9-9 of Fig. 8 with parts thereof broken away for clarity;

.Fig. 10 is an enlarged, fragmentary, vertical section taken along line 10-10 of Fig. 9 with parts thereof broken away for clarity;

Fig. 11 is an enlarged side elevation of a. segmented takeup end capstan forming part of an alternative embodiment of the invention with parts thereof broken away for clarity.

Fig. 12 is a fragmentary vertical section taken along line 12-12 of Fig. 11, and

Fig. 13 is a fragmentary, vertical section of a strandengaging sheave unitforming part of a second alternative embodiment of the invention.

Referring now to the drawings and more particularly to Figs. 1 and 2, there is shown a schematic arrangement of an apparatus designed to advance a plurality of steel strands 13-13 from left to right through an electroforming apparatus indicated generally at 14, which is designed to deposit a heavy coating of copper electrolytically on the strands.

Only three of the strands 13-13 are shown in Figs. 1 and 2 for purposes of illustrating the invention, but it is to be understood that the number of strands may be varied as desired, and may in actual practice amount to as many as twenty-five strands. The electroforming apparatus 14 does not form a pertinent part of the present invention and hence will be described herein only insofar as is necessary for a complete understanding of the invention.

The electroforming apparatus 14 (Figs. 1 and 2) includes an elongated trough 1, in which are positioned a series of shallow, rectangular tanks 16-16, twelve of which are shown in Figs. 3 and 4 to illustrate the general construction of the electroplating apparatus. The tanks 16-16 are filled with cleaning solutions and electroplating solutions, and are arranged serially in the trough 15 to electrolytically clean and pickle the steel strands 13-13v and thereafter to deposit a heavy coating of copper electrolytically on the steed strands as they are advanced through the electroforming apparatus.

Rotatably journaled in the side walls of the elongated trough 15 are a plurality of transversely mounted, metallic lower and upper contact rollers. Several lower contact rollers 17-17 and upper contact rollers 18-18 are shown in Figs. 1 to 4, inclusive. The strands 13-13 pass over the lower contact rollers 17-17 and under the upper contact rollers 18-18, which are provided with equally spaced peripheral grooves 19-19 designed to maintain a predetermined spaced relationship between the strands asthey are advanced through the tanks 16-16. In operation a positive D. C. potential is applied to the tanks 16-16, and the upper and lower contact rollers 17-17 and 18-18 are connected to a negative D. C. potential, so that the solutions contained in the tanks 16-16 clean the steel stands 13-13 electrolytically and deposit a relatively thick coating of copper electrolytically on the strands.

The steel strands 13-13 (Fig. 1) are withdrawn from supply reels 23-23, positioned in a stationary manner on stands 24-24 mounted on a base 25, by a magnetic capstan indicated generally at 28. The magnetic capstan 28 is mounted on a support 29 adjacent to the left end of the trough 15, and isv driven by an adjustable speed D. C. motor 30 regulated to operate at a constant preselected speed. Each individual strand 13 passes over an associated snubber sheave 33 and around an associated brahe sheave 34 mounted on an elongated support 35. From the brake sheaves 34-34 the respective strands 13-13 pass to a bank of guide sheaves 37-37 which fan out the strands and direct them toward a bank of snubber sheaves 38-38 mounted rotatably on a shaft 36 secured to the support 29.

The sheaves 38-33 are positioned spacedly on the shaft 36 so as to space the strands 13-13 apart a distance capstan is rotated at the constant preselected speed in a clockwise direction, as viewed in Fig. 1, by the motor 30, and withdraws the strands 13-13 from their respec tive reels 23-23 at a fixed linear speed.

The supply reels 23-23 are supported in a stationary position as indicated in Fig. 1, and each strand 13 revolves around the central axis of the upper head of its respective reel as it is withdrawn therefrom. The steel strands 13-13 normally have a tendency to unwind from the reels 23-23 due to the inherent resiliency of the strands and as a result, the outer convolutions on the reel tend to spring away from the reel and become entangled and break as they are withdrawn therefrom. To prevent this condition from occurring, each of the strands 13-13 engages a guide sheave 40 supported on the end of an arm 41 mounted rotatably on a cap 42 designed to fit neatly over the head of the reel 23 from which the strand isbeing withdrawn. Suitable braking means, not shown, is provided for resisting the rotation of the arm 41 with respect to the cap 42 and the reel 23 with a force sufficient to prevent the convolutions of the strand 13 from unwinding from around the reel faster than the strand is Withdrawn from the reel. The brake sheaves 34-34 mounted on the support 35 apply additional tension to their respective strands and assist the arms 41-41 in maintaining apredetermined tension on the strands between their supply reels 23-23 and the magnetic capstan 28.

A stand-by strand supply reel 23 (Pig. 7) is provided for each of the strands 13-13 to be advanced through the electr'oforming apparatus 14 to provide substantially continuous feeding of the strands through the 'electroforming apparatus. The stand-by supply reels 23-23 are positioned adjacent to the reels 23-23 from which the strandsare being withdrawn, as shown in Fig. 7, and'the inner ends of the strands 'being advanced through the electroforming apparatus 14 are connected to the outer ends of the strands wound on their respective stand-by supply reels. When 'a strand 13 is exhausted from its respective reel 23, the strand then is Withdrawn from the stand-by reel 23. A reel having a full strand supply their is positioned on the support 25 in place of the empty reel, and the outer end thereof is connected to the inner end of the reel from which the strand is being withdrawn. Thus, a continuous supply of strands 13-13 is provided for the electroforming apparatus 14.

The strands 13-13 (Fig. l) leave the magnetic capstan 28 at the preselected, fixed linear speed,pass over and under the series of contact rollers 17-17 and 18-18, respectively, and then partly around a segment'ed tensioning capstan 44 mounted on the support 29 at the right hand end of the trough 15 '(Fig. 2). The tensioning capstan 44 (Figs. 8, 9 and 10) comprises a plurality of separate, strand-engaging, sheave units 45-45 mounted on a common, rotatable drum 46 driven by an adjustable speed, D. C. motor 47 which is regal-- lated to operate at a constant pre-selected speed. Each of the strand-engaging sheave units 45-45 (Fig. '10) includes a wear ring 49 made of a wear-resistant metal, such as low manganese steel or the like, and having a J-shaped peripheral groove 50 in which a strand 13 is received. The grooved wear rings 49-49 are equally spaced to maintain the same spacing of the strands 13-13 as is provided by the peripheral grooves 19-19 in the contact rollers 17-17 and 18-18. The strands 33-13 pass around a substantial portion of the annular grooves 50-53 in the strand-engaging, sheave units -45 in a clockwise direction, as viewed in "Fig. 2, and then partly around a bank of snubber sheaves similar to the snubber sheaves 38-38, one of which is shown at 52 in Fig. 2.

The snubber sheaves 52-52 are mounted rotatably on a sha t 53 secured to the support 29 in the same manner that sheaves 33-38 are mounted on the shaft 36. The sheaves 52-52 direct the copper-clad strands 13-13 to a bank of sheaves 54-54 supported individually and rotatably on the support 35 so as to guide their respective strands toward sheaves 55-55, which in turn guide their respective strands to distributing rollers 56-56 mounted on a reciprocable distributor bar 57. The bar 57 is reciprocated continuously and longitudinally by suitable means (not shown) so as to distribute the strands 13-13 uniformly across the winding surfaces of take-up reels 58-58 supported rotatably be tween bearings 59-59 mounted on the base 25.

Each take-up reel 58 is driven by a separate constant horsepower D. C. motor 63 through a sprocket and chain drive indicated generally at 61. The constant horsepower motors 649-68 maintain substantially constant, predetermined tensions on the individual strands 13-13 be tween the segmented, tensioning capstan 44 .and the take-up reels 58-58 as the winding diameters or the take-up reels increase from an empty reel conditionto a full reel condition. individual electric switches (not shown) are provided for each of the motors -60, and may be operated selectively to stop a particular motor when its associated reel 53 has become full in order to remove the reel from the bearings 59-59 and replace it with an empty reel.

The magnetic capstan 23 (Figs. 5 and 6) is designed to grip the steel strands 13-13 magnetically in the peripheral grooves 39-39, as the capstan is rotated, and to feed the strands to the tensioning capstan 44, positioned at the opposite end of the apparatus 14, at a fixed linear speed equal to the peripheral speed of the grooves 39-39 of the magnetic capstan 28.

The magnetic capstan 28 (Fig. 5) is a 'sectionalized structure in which circular end plates 65 and 66 and circular intermediate plates 67-67, made of a paramagnetic material, are keyed on a shaft 68, and are spaced apart by annular cores 70-70, also made of a paramagnetic material. The plates 67-67 and the cores 73-79 are clamped together between the'end plates 65 and 66 by a plurality of tie rods 71-71. Circular bands 72-72, made of a nonmagnetic material, are fitted into annular shoulders 73-73 formed in the peripheries of the end plates 65 and 66 and the intermediate plates 67-67, so that the assembly of the bands and the-plates form a cylinder having a smooth outer surface. End rings 74-74 and intermediate rings 75-75, made of a magnetic material, fit neatly over the assembly of the end plates, the intermediate plates and the circular bands, and are spaced apart by thin, annular spacers 76-76 made of a nonmagnetic material. End rings 78-78, made of a nonmagnetic material, such as bronze, fit neatly over the end rings 74-74, and intermediate rings 79-79, made of the same nonmagnetic material, fit neatly over the rings 75-75. 1 Y

The rings 74-74, 75-75, 78-78 and 79-79 (Figs. 5 and 6) are keyed to the end plates 65 and 66, the intermediate plates 67-67 and the annular bands 72-72 by headless set screws 80-80. The adjacent sides of these rings are beveled so that the sides of the rings and the'peripheries of the spacers form the grooves 39-39 in the periphery of the capstan 28; The grooves 39-39 are designed to extend into the steel rings 74-74 and 75-75, toward the central axis of the capstan 28, a distance equal to approximately one-half the diameter of the strands 13-13 to be advanced by the capstan. Magnet coils 82-82 are positioned over the steel cores 70-70 clamped between the plates 67-67, and are connected in series with each other. One lead wire of the left hand coil 82 (Fig. 5) and one lead wire of the right hand coil 82 are connected to collector rings 84 and 85, respectively, mounted on a plate 86, made of a suitable insulating material, and secured to the shaft 68. The shaft 68 is journaled in bearings 90 and 91 and has a sprocket 92 secured on the shaft which engages an endless chain belt 93 driven by a sprocket mounted on the shaft of the motor 30.

When a suitable 'D. C.. potential is applied across the collector rings 84. and 85, the magnetic coils 82-82 generate magnetic flux which flows longitudinally through the cores 70-70 radially through the plates 65 and 66 and 67-67, and longitudinally through the rings 74-74 and 75-75 so as to form an annular magnetic field around each of the grooves'39-39. In describing the path of the magnetic flux generated by each magnet coil, the respective positions of the coils, theplates and the rings with respect to each other shall be identified by counting from left to right, as viewed in Fig. 5.

The magnet coils 82-82 may be wound around their respective cores 70-70 in such a directiomand may be connected together and to a source of D. C. potential in such a manner that the odd number coils generate a magnetic flux which travels from left to right through their respective cores, and the even number coils generate a magnetic flux which travels from right to left through their respective cores. Under these conditions the magnetic flux generated by the coils flows outward radially through the odd number intermediate plates 67-67 and inwardly radially through the end plate 65 and the even number intermediate plates 67-67 as indicated by the arrows in Figs. 5 and 6. Thus, the magnetic flux generated by each magnet coil 82 forms an annular magnetic field around only the two grooves 39-39 which encircle the coil, and attracts only the strands 13-13 engaged by these grooves. As a result, only one magnet coil 82 is required for each pair of wires to be advanced by the magnetic capstan 28. By virtue of this construction, the magnetic capstan 28 may be arranged, by selection of the proper number of magnet coils, 'circular plates and rings, to withdraw a substantial number of steel strands 13-13 from their respective supply reels 23-23 and feed them to the electroforming apparatus 14 and the capstan 44 at a fixed linear speed.

The magnet coils 82-82 are designed to generate a magnetic flux of sufficient magnitude to grip the strands 13-13 and maintain the linear speed thereof substantially equal to the peripheral speed of the grooves 39 39 of magnetic capstan 28 at all times against a predetermined pull applied to the strands by the contact rollers 17-17 and 18-18, and the tensioning capstan 44 and the take-up reels 58--58. The magnetic capstan 28 is described more fully and claimed in copending application, Serial No. 238,521, filed July 25, 1951 by D. E. Koerner for Strand Advancing Apparatus.

To limit and control the rate of wear on the contact roller grooves 19-19, and to prevent a build-up of excessive strand tensions, all of the contact rollers 17-17 and 18-18 are positively driven at constant speeds such that the peripheral speeds of the contact roller grooves exceed by predetermined amounts the preselected, fixed linear speed of the strands 1.3-13. The contact rollers 17-17 and 18-18 are grouped on separate drive units.

sisting of two lower each powered by its own motor-so that each carries'a definite portion of the total contact roller load.

As shown in Fig. 1, the two of the lower contact rollers 17-17 and the upper contact roller 18 positioned' nearest to the magnetic capstan 28 form a group and'are driven rotatablyin clockwise and counterclockwise directions, respectively, by the D; C. motor 30, which also drives the magnetic capstan ,ata constant, preselected speed. Themotor 30 is connectedby means of an endless drive chain 94 to a jack shaft 95, which'in turnis connected to each of the above-mentioned group of con-' tact rollers 17-17 and 18 by means of an endless drive chain 96 provided with a suitable chain tensioning unit. The gear train ratio is such that each roller of .this group l; ofcontact rollers 17-17 and 18 nearest to themagnetic capstan 28 has a constant, preselected, peripheral speed which is approximately 1.8%- greater than the peripheral speed of the magnetic capstan.

At the right end of the electroforming apparatus 14 I (Fig. 2), the'two lower contact rollers 17-17 and'the upp'er contact roller 18 nearest to the segmented' ten-: sioning capstan 44' form another group and are driven rotatably in clockwise and counterclockwise directions; respectively, by the D. C. motor 47 connected .by means of a drive chain 97 to a jack shaft 98, which in tu'rnis connected through a common drive chain 99 provided with a suitable chain tensioning unit to each of the contact rollers 17-17 and 18 of the group. This'last-mentionedgroup of contact rollers 17-17 and 18 is designcdto be driven so as to have a constant preselected peripheral speed which is approximately 2.8% greater than the peripheral speed of the magnetic capstan 28.

The remaining lower contact rollers '17-17 and -upper contact rollers l8-18 intermediate of the aforementioned groups are similarly driven in. groups of three concontact rollers 17-17 and the upper contact roller 18. positioned therebetween, Each of the intermediate groups of contact rollers 17-17 and 18. is driven by an associated adjustable speed D. C. motor 100, which is speed regulated to operate at a constant preselected speed through a common drive chain 101 provided with a suitable chain tensioning unit. The peripheral speeds of the contact rollers 17-17 and 18- in any one group are equal,v but the peripheral speeds of the contact rollers 17-17 and 18 of the different groups vary by graduations from a. speed 1.8% greater than the peripheral speed of the magnetic capstan 28 for the group nearest the magnetic capstan to 2.8% greater for the group nearest to the segmentedtensioning capstan 44' The reason for the graduated increase in the percentage of overdrive of the rollers 17-17 and 18-18: of the various groups is that the strands 13-13 are expanding as they move progressively through the series of tanks 16-16 containing warm electroplating solutions and they are elongating temporarily due to their elasticity under tension. I

It will be understood that the number of lower and upper contact rollers 17-17 and 18-18 arranged in any one group to be driven by a common drive unit is not limited to any specific number. For the convenience of illustrating and describing the invention, only three con tact rollers are shown comprising each group. However,

in actual practice it may be found more suitable to group as many as ten contact rollers 17-17 and 18-18 on each separate drive unit.

The segmented tensioning capstan 44 is shown in de-,

tail in Figs. 8, 9 and 10. The cylindrical drum 46 of the capstan 44 is secured at its ends to a pair of circular headplates, one of which designated 102 is shown in Fig. 9. .The headplates 102-102 are keyed on a shaft 103 for rotation therewith. vMounted on the ends of the. drum 46 are flanged retaining rings 104 and 105, whichare secured detachably to the-drum by means of aplu rality of long dog point setscrews 107-107.

Each of the strand-engaging sheave units 45-45 includes, in addition to the grooved wear ring 49, a pair of complementary, annular, sheave halves 110-110 made of an electrical insulating material, such as Micarta or the like. The outer periphery of each of the sheave halves 110-110 is provided with an annular recess 111, and theinner periphery thereof is provided with an annular recess 112. A plurality of tubular rivets 113-113 hold each pair of sheave halves 110-110 tightly together so that they grip an annular rib 114 formed on the inner periphery of the associated wear ring 4-9 fixedly between the shoulders of the complementary recesses 111-111.

lThepairs of sheave halves 110-110 are similarly secured fixedly to an annular, outer race 115 of a ball bearing assembly 116, which is gripped tightly between the shoulders of the complementary recesses 112-112 formed on the inner periphery of the sheave halves. The outer race 115 has formed in its inner periphery an arcu ate groove 117, which provides an outer raceway for a plurality of ball bearings 118-118. The inner raceway for .the ball bearings 118-118 is provided by opposed, concave shoulders 120-120 on a pair of annular, inner races 122-122. Suitable protecting shields 124-124 are attached to the opposite sides of the outer races 115-115 forthe purpose of retaining a lubricant and for prevent ing foreign matter from entering and fouling the ball bearings 118-118 and their raceways.

The annular inner races 122-122 of each of the strand-engaging sheave units 45-45 are designed to fit snugly but slidably upon the drum 46, so as to be capable of being moved axially relative to each other to increase or "decrease the pressure exerted by their raceways on the retained ball bearings 118-118. The drum 46 has a true, finely finished surface and is made of bronze or bearing brass to minimize friction resistance. The inner races 122-122 of each strand-engaging sheave unit 45 are provided on their opposite sides with annular flanges 127-127, each of which is designed to make abutting contact with an identical flange on the adjacent inner race 122 of an adjacent strand-engaging sheave unit 45.

The series of strand-engaging sheave units 45-45 are mounted on the drum 46 with the flanges 127-127 of the inner races 122-122 in abutting contact, and the inner races are forced together axially by a flanged pressure ring 130. As viewed in Fig. 10, the flanged pressure ring 130 is urged axially to the left by means of a plurality of compression springs 132-132 spaced equally around the pressure ring and disposed between the latter and the retaining ring 105. Each of the compression springs 132-132 is mounted on a retaining pin 133 having one end thereof secured fixedly to the pressure ring 130 and the other end slidably received within an axial bore 134 formed in an externally threaded adjustment nut 135, which in turn is received within an internally threaded aperture 136 formed in the retaining ring 105.

When the adjustment nuts 135-135 are rotated clockwise, as viewed in Fig. 9, the compression springs 132- 132 are compressed between the ends of the adjustment nuts 134-134 and the pressure ring 130, thereby resiliently urging the pressure ring 130 to the left, as viewed in Fig. 8. This forces the abutting flanges 127-127 on the inner races 122-122 of adjacent strand-engaging sheave units 45-45 tightly together and against the retaining ring 104.

By selectively positioning the threaded adjustment nuts 135-135 axially, the pressure exerted by the opposed shoulders 120-120 of each pair of inner races 122-122 on their associated ball bearings 118-118 may be adjusted equally. The pressure exerted by the compression springs 132-132 and the friction between the drum 46 and the internal surfaces of the inner races 122-122 are always sufiicient under normal conditions to prevent relative rotation 'between the inner races and the periphery of the drum with the exception of an imperceptible .creep inherent in such'structures. For a given operation, the

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pressure is adjusted to permit rotation of the grooved wear ring 49 and the associated, attached, outer race 115 of each strand-engaging sheave unit .45 relative to their respective inner races 122-122 and the drum 46*when the frictional pull of the Wear ring 49 on its contained strand 13 exceeds a predetermined value (F).

The adjustable-speed, D. C. motor 47 is connected to the shaft 103 bymea'ns of a drive chain 140 (Fig. 4), and its speed'regulated to drive the drum 46 at a constant preselected speed suchthat at a no load condition, when there is no rotation of the wear rings 49-49 with respect to the drum '46, the peripheralspeed of the grooves -50 .of-the wear rings exceeds the'peripheral speed of the grooves:3-9-39 'on the magnetic capstan 28 by approximately 30%.

it 'should'be noted that the total torque applied to the shaft 103 must be at least sulficient to pull alluof the strands 13-13 with a predetermined .frictionalpull (.F) on each of them, but that no matter how many less strands than the full complementare running over the segmented, tensioning capstan 44, no one strand will at any time'be subjected to more'than this predetermined frictional pull (F because of the independent slipping provision for each of the grooved wear rings 49-49.

' OPERATION Let it be assumed that the electroforming apparatus 1'4-is supplied with the proper cleaning and electroplating solutions, and'that all of the steel strands 13-13 to be advanced through the electroplating apparatus have been properly threaded from their respective supply reels 23-23 around the magnetic capstan 28, over and under the rollers 17-17 and 18-18, respectively, around the strand-engaging sheave units 45-45 on the segmented, tensioning capstan 44, and secured to their respective take-up reels 58-58. 'The magnet coils 82-82mm:

energized by connections to a suitable D. C. potential,

and the coils generate magnetic fiux which tends to'hold the strands 13-13 magnetically in the grooves 39-39 of the magnetic capstan 28.

The adjustable speed D. C. motors 30, 47 and 100- 100, and the constant horsepower, take-up reel, D. C. motors -60 are electrically interconnected in an electrical control system (not shown in its entirety), which includes a tachometer generator 140 and a pilot. generator 141 (Fig. 3) operatively connected to the shaft of the D. C. motor 30. The tachometer generator 140 is arranged to maintain the desired speed controland coordination between the respective adjustable speed D. C. motors 30, 47 and -100 to insure at all conditions the predetermined speed ratios between the mag netic capstan 28, the segmented tensioning capstan 44 and the contact rollers 17-17 and 13-18. The characteristic operating curves of the D. C. motors '30, 47 and 100-100 and the functioning of the control system are such that these motors perform substantially alike under normal no-load to full-load conditions. The pilot generator 141 functions to coordinate the outputs of the constant horsepower take-up reel D. C. motors 60-60 with the speed of the magnetic capstan 28, which in turn determines the fixed iinear speed of the strands 13-13 being taken up by their take-up reels 58-58.

The magnetic capstan 28 is driven by the constant speed D. C. motor 30 at a predetermined speed, and withdraws the strands 13-13 from their individual supply reels 23-23 and feeds them to the electroforming apparatus 14 at a constant predetermined linear speed. As long as the tensions in the strands 13-13 on the recess side of the magnetic capstan 28 do not exceed a predetermined maximum safe value, which value is by design much greater than normal strand tensions prevailing during an operation, there can be no slip of the strands 13-13 in the grooves 39-39 of the magnetic capstan 28 to introduce variations in the predetermined constant strand speed. Thus, the magnetic capstan 28 functions as a speed governor for letting out or metering the strands 13-13 simultaneously to the electroplating apparatus 14 at a predetermined fixed rate.

The constant horsepower D. C. motors 60-60, which drive the individual take-up reels 58-58, maintain substantially constant, preselected tensions on the individual strands 13-13 at the recess side of the segmented, tensioning capstan 44 throughout the operation. For the purposes of this description, it will be assumed that the constant horsepower motors 60-60 establish such a constant tension (T) in each of the individual strands 13-13. Further, it will be assumed that theforce exerted by the pressure ring 130 is such that the grooved wear rings 49-49 of the individual strand-engaging sheave units 45-45 on the capstan 44 rotate relative to the drum 46 when the frictional pull exerted on their respective strands 13-13, as a result of strand-to-wear ring friction, reaches a predetermined value (F).

The frictional pull (P), which each of the strand-engaging sheave units 45-45 will impart to its respective strand 13, may be preselected within limits by selectively adjusting the adjustment nuts 135-135 in the manner heretofore described to increase or decrease the frictional drag between the ball bearings 118-118 and their associated outer and inner races 115 and 122-122, respectively. The frictional pull (F) imparted by each of the individual strand-engaging sheave units 45-45 to its respective strand 13 augments the tension (T) previously established in the strand by the associated take-up reel motor 60, so that the tension in each of the strands 13-13 on the approach side of the segmented, tensioning capstan 44 is equal to their sum (T+F).

Each of the overdriven contact rollers 17-17 and 18-18 contributes in turn to the tension in each of the strands 13-13 as a result of strand-to-contact roller friction. The extent of slippage between the individual strands 13-13 and the overdriven contact rollers 17-17 and 18-18 does not affect the pull on each strand contributed by the roller. The absolute amount of the overdrive is therefore not a criterion in tension control, but must be limited only in the interest of reducing roll wear. On the low side there must be enough overdrive to prevent slack from accumulating in the strands.

The effect of the frictional pull contributed 'by each of the overdriven contact rollers 17-17 and 18-18 is such that the tension in each strand increases towards the supply end of the electroforming apparatus 14, so that the point of highest strand tension prevalls in each strand between the magnetic capstan 28 and the lower contact roller 17 nearest to the magnetic capstan28. The frictional pull contributed by each of the contact rollers 17-17 and 18-18 is a function of the coefiicient of friction between a given strand 13 and the contact roller engaged thereby, the angle of wrap of the strand on that roller and the tension on the slack or recess side of that roller. The coefiicient of friction between a strand and a given contact roller may be considered constant, as is the angle of wrap for any given contact roller. Thus, the frictional pull contributed by each of the contact rollers 17-17 and 18-18 may be expressed as a logarithmic function of the tension in the strand on the slack or recess side of the particular roller.

For example, the lower contact roller 17 immediately adjacent to the segmented, tensioning capstan 44 increases the tension in each of the strands -10 by an amount equal its frictional pull (Fr). This frictional pull (Fr) may be expressed in terms of the tension (T) established at the take-up reels 58-58 and the frictional pull (F) imparted by the strand-engaging units 45-45 of the tensioning capstan 44 as follows:

Fr=( l .throughout the electroforming apparatus 14.

where t-'-the coefficientof friction between the given contact roller and the strand. 0=the angle of wrap in radians.

Since the tensions in the strands 13-13 approaching any one of the overdriven contact rollers 17-17 and 18-18 are logarithmic functions of the tensions in the strands at the recess sides of the rollers, it 'follows'that control of tensions in the strands 13-13 throughout the entire electroforming apparatus 12 devolves to a relatively simple procedure of controlling either the tension (T) established by the individual take-up reel motors 60-60 or the frictional pull (F) contributed by the "separate strand-engaging units 45-45 of the segmented, tensioning capstan 44. The facility with which the frictional pull (F) of the strand-engaging units 45-45 of the capstan 44 maybe adjusted'to a preselected value makes the latter method most suitable.

Any increase or decrease in the frictional pull (F), contributed by each of the strand-engaging units 45-45 of the tensioning capstan 44, is reflected all the way back through the electroforming apparatus 14 to the magnetic capstan 28. Thus, while the take-up reels 58-58 driven by their respective constant horsepower motors 60-60 originate basically and determine the order of the strand tensions, the segmented, take-up end capstan 44 is utilized as the tension-controlling device for establishing within a predetermined range the desired strand tensions 'As' mentioned previously, as long as the established tensions in the strands 13-13 on the recess side of the magnetic'capstan 28 do not exceed a predetermined safe operating value, there cannot be any slippage between the individual strands and the magnetic capstan. Thus, the magnetic capstan 28 not only serves as a speed-governing device, but also serves the additional function of a holdback device permitting the establishment of strand tensions independently of the strand speed by the contact rollers 17-17 and 18-18, the segmented, tensioning capstan 44, and the take-up reels 58-58.

It is obvious that the above-described apparatus permits the strands 13-13 to be advanced simultaneously and continuously through the electroforming apparatus 14 atthe constant predetermined linear speed established by the magnetic capstan 28. The tensions in the strands are established independently of this predetermined strand speed, and may be preselected withina predetermined range by the simple expedient of adjusting the adjustment nuts -135 to change the force exerted on the inner races 122-122 of the individual strand-engaging units 45-45. Since it was assumed that the tensions established in each of the strands 13-13 between the take-up reels 58-58'and the capstan 44 were equal with a given setting of the segmented, tensioning capstan 44, the tensions in the strands in any one section of the electroforming apparatus 12 are equal and remain substantially constant throughout the operation.

On the recess side of the magnetic capstan 28 where the strands 13-13 enter the electroforming apparatus 14, the baresteel is springy and highly subject to snarling and kinking if it is allowed to'grow-slack,-but its surface is hard, smooth, and not easily damaged by rubbing or scraping. Thus, the strands 13-13 at the entry end of the apparatus 14 require higher tensions and are well'able to tolerate them. Where the finished copper-clad strands '11 13-13 leave the electroforming apparatus 14, they are much deader, stifler and lessliable to kinking, but their platedsurfacesare soft'and easily scraped, crushed or marred. Thus, the finished strands 13-13 at the exit end of the apparatus 14 should not be subjected to high tensions, and fortunately do not require thern.

The aforementioned strand tension requirements are uniquely satisfied by the above-described apparatus in which the pull added by each of the successive contact rollers 17-17 and 18-18 increases thetension in the strands 13-13 section by sectionina direction opposite to the direction of movement thereof, whereby the greatest tension in the strands occurs in the section between the magnetic capstan '28 and the contact roller 17 immediately adjacent thereto.

First alternative embodiment Illustrated in Figs. Hand 12 is a segmented, tensioning capstan 144 which, may be substituted for the segmented,-tensioning capstan 44 heretofore described and driven by a D. C. motor identical with the motor 47-, without changing the overall manner of operation of the apparatus.

Referringto the Figs. 11 and 12, the*capstan 144 is secured to a shaft 150 supported retatably at itsfiendsin suitable bearings (not shown). The shaft 150 is arranged to :be driven by a motor like the motor 47 througha drive chain like the chain drive 140 shown in Fig. 4. The capstan 144 comprises a cylindrical metal drum 155 having a plurality of axially extending keyways 157-157 (Fig. 11). The drum 155 is secured at its ends to a pair of headplatcs 158-158, which in turn are secured to the shaft 150. A plurality of annular, metal driving discs 160-160 are slidably mounted on the drum 150, and have key-like projections 161-161 extending into the keyways 157-157 for interlocking the discs with the drum for rotation therewith. Between adjacent discs 160-160-are disposed annular, metal rings 163-163 having generally -shaped grooves 165-165 on their outer peripheries for receiving strands 13-13 therein.

The driving discs 160-160 are spaced apart by annular insulating spacers 167-167 of L-shaped cross sections having flat disc portions 168-168 and axially extending cylindrical flanges 169-169. The spacers 167-167 are arranged in pairs on opposite sides of the rings 163-163, with the disc portions 168-168positioned between the rings and the driving discs 160-160 and the flanges 169-169 directed toward each other in engagement with the inner periphery of the rings 163-163. The spacers 167-167 are supported on bushings 170-170 encircling the drum 150. The spacers 167-167 are proportioned to provide space between the adjacent end faces of the cylindrical flanges 169-169 to permit a slight movement ot' the spacers toward each other, and the bushings 170-170 are of such a width as to permit a slight axial movement of the driving discs 160-160 relative to each other.

The grooved rings 163-163 fit tightly onthe axially extending cylindrical flanges 169-169 of the insulating spacers 167-167, andeach of the bushings 170-170 fits tightly in the associated pair of spacers 167-167. The bushings 170-170 have a tree receiving fit on the drum 150 for free rotatable engagement therewith. With this construction, each of the grooved rings 163-163, together with its associated pair of spacers 167-167 and bushing 170, forms a strand-engaging unit, slidably and rotatably engaging the drum 150.

The series of metal driving discs 160-160, grooved metal rings 163-163 and spacers 167-167 are designed to be forced together axially to grip the grooved metal rings to form strand-engaging units for rotation with the drum. The pressure exerted on these units is adjusted to permit slipping of each of the individual unitsin the 'event a.pulling force exceeding a predetermined value (F) is exerted bythe ring 163 of a given unit on its respective 12 strand 10. The spacers 167-167 are pressed against thedriving discs 160-160 so that all rotational yield of the grooved rings 163-163 relative to the'drum takes place by virtue of slip between the spacers and the driving discs. The bushings 176-170' act as bearings for the strand-engaging units to revolve freely on the drum 150 except for the frictional restraint offered by' the driving discs -160.

'An annular flange is threadedly mounted on a threaded'end portion 176 of the drum 150 and is locked in adjusted position by a lock nut 177. The flange 175 serves as-a stop against which the series of annular driving discs 169-160, grooved rings 163-163 and spacers 167-167 :are pressed. An annular pressure .fiange 180 is keyed to the drum 150 for rotation therewith and with free axial movement thereon. The pressure flange 180=is designed to engage the other end of'the series of annular driving discs 160-160, grooved rings 163-163 and spacers 167-167, and is urged toward the flange $175 by a plurality of compressing springs arranged in acircle,

of which one designated 182 is shown in Fig. 11. The

springs 182-182 are seated at one end in recesses in the pressure flange 130 and at the other end in threaded retainers 183-183, which are 'adjustably mounted in a flange 185 and locked in adjusted position by lock nuts 187-187. The flange 185 is keyed to the drum 150 for rotation therewith and is locked in position by a lock nut 190.

By adjusting the position of the flange 185 axially on the drum 150 and by adjusting the retainers 183-183, the pressure of the springs 182-152 may be adjusted to exert a predetermined pressure against the flange 175 to cause the series of driving discs 169-160, grooved rings 163-163 and spacers 167-167 tobe forcedagainst each other between the flanges 175 and 180 with sufl'icient pressure to drive the rings 163-163 with the drum 150 up to a predetermined maximum torque. The value of thismaximurn torque is such that the individual grooved rings 163-163 may slip relative to the drum 150 in response to a predetermined frictional pull exerted by each of the. grooved rings on its respective strand 113. n

The spacers 167-167 may be molded, punched, out or otherwise formed from suitable electrical insulation material, such as phenol canvas. They also may be made of hard rubber or other suitable insulating material, if "desired. The metal driving discs 160-160 preferably are made of hardened and ground steel. The rings 163-163 are made of :a metal that is wear resistant, has a high co e flicientof friction, and also is a good conductor of electricity. For example, they may be made of Nichrome, manganese steel or the like. p

In some instances it may not be necessary to have the strand supporting ring electrically insulated from each other. In such case the spacers, such as the spacers 167-167, may be made of bearing bronze, Babbitt, cast iron or metallized graphite.

Although it is possible to substitute the tensioning capstan 144 for the tensioning capstan 44 without chang ing the overall manner of operation of the apparatus, it has been found that the capstan 44 is better suitcdto systems in which the tensions in the strands 13-13 are of a low order, whereas the capstan 144is better suited to systems in which the strands are under relatively higher tensions.

Second alternative embodiment Illustrated in Fig. 13 is a strand-engaging sheave unit 245 of a type which may be substituted for the strandengaging sheave units 45-45 of the segmented tensioning capstan 44 heretofore described without changing the mode of operation of the overall apparatus.

The sheave unit 245 is similar to the sheave units 45- 45 with the exception that the unit 245 has a ball hearing assembly 248 provided with two sets of ball bearings 250-250. To accommodate the two separate sets of ball bearings (}250, the ball bearing assembly 248 is provided with an annular outer race 254 having formed on its inner periphery an annular rib 257 having concave shoulders 259-259 forming outer raceways for separate sets of ball bearings. The inner raceways are provided by a pair of separate inner races 260-260 the outer peripheries of which are formed with complementary, spaced concave shoulders 262--262 against which the respective sets of ball bearings 250-250 are supported.

The inner races 260-260 are provided on their opposite sides with annular flanges 270-270, each of which is designed to make abutting contact with an identical flange on the adjacent inner race of an adjacent strandengaging sheave unit 245.

A series of strand-engaging sheave units 245245 are mounted, in a manner similar to that in which the aforementioned strand-engaging sheave units 45 are mounted, with the flanges 270270 of the adjacent inner races 260-260 of adjacent sheave units in abutting contact and forced together axially. By adjusting the force urging the pairs of inner races 2643-260 together axially, the frictional drag between the inner and outer races may be adjusted to a preselected value.

It will be understood that, although in the preferred embodiment all of the contact rollers 1717 and 1818 are overdriven, provisions may be made to permit the drive gear ratios to be changed so that if desired some of the rollers will have no overdrive relative to the strands 1313 and thus will not pull on the strands. This change can be extended further to a condition where some of the contact rollers are underdriven, in which case they will put a drag on the strands instead of a pull. When the latter condition occurs, the low tension or slack side of the strands will switch to the approach side of the particular underdriven contact roller, while the high tension or tight side of the strands will switch to the recess side of this roller. By means of a suitable selection of over and under driven contact rollers, it is possible to produce substantially uniform tensions on the strands throughout the machine. Thus, this invention makes it possible to obtain virtually any order of tension variations desired.

It also is to be understood that the term strand as used hereinabove and in the appended claims is meant to include solid wires, stranded Wires, tubing, tapes, ribbons and all types of articles of relatively small cross section and of indefinite length, which consist wholly of a paramagnetic material or have a paramagnetic core or covering. Such strands may be made in whole, or in substantial part, of steel or other suitable paramagnetic material. For the sake of simplicity all such materials are referred to hereinabove and in the annexed claims as paramagnetic materials.

While the above-described apparatus for advancing steel strands is particularly adapted to be used in the manufacture of copper-clad steel strands, it is to be understood that it may be readily modified to advance a plurality of strands individually through various types of apparatus without departing from the spirit and scope of the invention.

What is claimed is:

1. Apparatus for advancing a strand from a supply thereof along an elongated tortuous path to a take-up while maintaining a predetermined constant linear speed and a substantially constant predetermined tension in any given portion of the path, which comprises a strandmetering and hold-back means for withdrawing the strand from its supply and letting it out at a predetermined constant linear speed, and a strand-tensioning capstan for pulling the strand against the drag created by the strand-metering and hold-back means with a force tending to advance the strand faster than said predetermined linear speed, said captsan being designed to yield rotationally whenever the torque applied thereto 14 resulting from the frictional drag exerted by the strand on the capstan exceeds a predetermined value.

2. Apparatus for advancing a strand from a supply thereof along an elongated tortuous path to a take-up while maintaining a predetermined constant linear speed and a substantially constant predetermined tension in any given portion of the path, which comprises a strand metering and holdback means for withdrawing the strand from its supply and letting it out at a predetermined constant linear speed, and a strand-tensioning capstan for pulling the strand against the drag created by the strand-metering and hold-back means with a force tending to advance the strand faster than said predetermined linear speed, said capstan including a grooved, strand-engaging sheave designed to yield rotationally Whenever the torque applied thereto resulting from the frictional drag exerted by the strand on the sheave exceeds a predetermined value.

3. Apparatus for advancing a strand from a'supply thereof along an elongated tortuous path to a take-up while maintaining a predetermined constant linear speed and a substantially constant predetermined tension in any given portion of the path, which comprises a strandmetering and hold-back means for withdrawing the strand from its supply and letting it out at a predetermined constant linear speed, a strand-tensioning capstan for pulling the strand against the drag created by the strand-metering and hold-back means with a force tend ing to advance the strand faster than said predetermined linear speed, said capstan including a strand-engaging sheave designed to yield rotationally whenever the torque applied thereto resulting from the frictional drag exerted by the strand on the sheave exceeds a predetermined value, and means for adjustably presetting the amount of the torque required to cause the sheave to yield rotationally.

4. Apparatus for advancing a plurality of individual strands simultaneously from individual supplies thereof along an elongated, tortuous path to individual take-up reels at a predetermined linear speed and under substantially constant, equal tensions, which comprises a strand-metering and hold-back means for withdrawing the strands simultaneously from their supplies and letting them out at a predetermined constant linear speed, and a segmented strand-tensioning capstan for pulling each of the strands against the drag created by the strand-metering and hold-back means with a force tending to advance thestrand faster than said predetermined linear speed, said capstan including a plurality of strandengaging sheaves each of which is designed to yield rotationally individuallywhenever the torque applied thereto resulting from the frictional drag exerted thereon by its respective strand exceeds a predetermined value.

5. Apparatus for advancing a plurality of individual strands simultaneously from individual supplies thereof along elongated, tortuous parallel paths to individual takeup reels at a predetermined linear speed and under substantially constant equal tensions, which comprises strand-metering and hold-back means for withdrawing the strands simultaneously from their supplies and letting them out at predetermined constant linear speed, and a segmented, strand-tensioning capstan coacting for pulling each of the strands with a force tending to advance the strand faster than said predetermined linear speed, said strand-tensioning capstan including a rotatable shaft member and a plurality of individual strand-em.

gaging elements mounted thereon and over which the strands pass, each of said strand-engaging elements being frictionally engaged with the shaft member for rotational movement therewith and designed to yield rotationally with respect to the shaft member when the torque applied thereto resulting from the frictional pull exerted thereon by its respective strand exceeds a predetermined value.

6. Apparatus for advancing a plurality of individual strands simultaneously from individual. supplies thereof along elongated, tortuous parallel paths to individual take-up reels at a predetermined linear speed and under substantially constant equal tensions, which comprises strand-metering and hold-back means for withdrawing the strands simultaneously from their supplies and letting them out at a predetermined constant linear speed, a segmented, strand-tensioning capstan coact-ing for pulling each of the strands with a force tending to advance the strand faster than said predetermined linear speed, said strand-tensioning capstan including a rotatable shaft member and a plurality of individual strand-engaging elements mounted thereon and over which the strands pass, each of said strand-engaging elements being frictionally engaged with the shaft member for rotational movement therewith and designed to yield rotationally with respect to the shaft member when the torque applied thereto resulting from the frictional pull exerted thereon by its respective strand exceeds a predetermined value, and means for adjustably presetting the degree of fric tional engagement between the strand-engaging elements and the rotatable shaft member.

7. Apparatus for advancing a plurality of individual strands simultaneously from individual supplies thereof along elongated, tortuous parallel paths to individual take-up reels at a predetermined linear speed and under substantially constant equal tensions, which comprises strand-metering and hold-back means for withdrawing the strands simultaneously from their supplies and letting them out at a predetermined constant linear speed, and a segmented, strand-tensioning capstan coacting for pulling each of the strands with a force tending to advance the strand faster than said predetermined linear speed, said strand-tensioning capstan including a rotatable drum and a plurality of individual, annular strand-engaging sheaves mounted side-by-side on the drum in coaxial relationship therewith, each of said strand-engaging sheaves being frictionally engaged with the shaft member for rotational movement therewith and designed to yield rotationally with respect to the shaft member when the torque applied thereto resulting from the frictional pull exerted thereon by its respective strand exceeds a predetermined value.

8. Apparatus for advancing a plurality of individual, paramagnetic strands simultaneously from individual supplies thereof along an elongated, tortuous path to individual take-up reels at a predetermined linear speed and under substantially constant, equal tensions, which comprises a common magnetic capstan for withdrawing all of said strands simultaneously from their supplies, 7,

drive means for rotating the magnetic capstan at a predetermined constant peripheral speed, magnetizing means associated with the magnetic capstan and so designed as to magnetically hold each strand individually against the capstan with such force that the strands are advanced by the capstan without slippage of the strands on the capstan and at a linear speed equal to the peripheral speed of the capstan, and a segmented, strandtensioning capstan coacting for pulling each of the strands with a force tending to advance said strand faster than said predetermined linear speed, said strand-tensioning capstan including a rotatable shaft member and a plurality of individual strand-engaging elements mounted thereon and over which the strands pass, each of said strand-engaging elements being frictionally engaged with the shaft member for rotational'movement therewith and designed to yield rotationally with respect to the shaft member when the torque applied thereto resulting from the frictional pull exerted thereon by its respective strand exceeds a predetermined value.

9. Apparatus for advancing a plurality of individual, paramagnetic strands simultaneously from individual supplies thereof along an elongated, tortuous path to individual take-up reels at a predetermined linear speed and under substantially constant, equal tensions, which comprises a common magnetic capstan for withdrawing all of said strands simultaneously from their supplies, drive means for rotating the magnetic capstan at a predetermined constant peripheral speed, magnetizing means associated with the magnetic capstan and so designed as to magnetically hold each strand individually against the capstan with such force that the strands are advanced by the capstan without slippage of the strands on the capstan and at a linear speed equal to the peripheral speed of the capstan, and a segmented strand-tensioning capstan coacting for pulling each of the strands with a force tending to advance said strand faster than said predetermined linear speed, said strandtensioning capstan including a rotatable shaft member, a plurality of individual strand-engaging elements mounted thereon and over which the strands pass, each of said strand-engaging elements being frictionally engaged with the shaft member for rotational movement therewith and designed to yield rotationally with respect to the shaft member when the torque applied thereto resulting from the frictional pull exerted thereon by its respective strand exceeds a predetermined value, and means for adjustably presetting the degree of frictional engagement between the strand-engaging elements and the rotatable shaft member.

10. An apparatus for advancing a plurality of individual, paramagnetic strands simultaneously from individual supplies thereof along an elongated tortuous path to individual take-up reels at constant, equal linear speeds and under substantially constant equal tensions, which comprises a common magnetic capstan for Withdrawing all of said strands simultaneously from their supplies, cans for rotating the magnetic capstan at a constant peripheral speed, magnetic means associated with the magnetic capstan and so designed as to magnetically hold each strand individually against the capstan with such force that the strands are advanced by the capstan without slippage of the strands on the capstan and at a linear speed equal to the peripheral speed of the capstan, a segmented strand-tensioning capstan including a rotatable member, and a plurality of individual, annular, strand-engaging sections arranged side-by-side on the rotatable member in coaxial relationship therewith and normally frictionally engaged with the rotatable member for rotation therewith, each of said sections being designed to yield rotationally with respect to the rotatable member whenever the torque resulting from a frictional; pull exerted thereon by its respective strand exceeds a predetermined value, and means for driving the rotatable member at a speed such that when the strand-engaging sections do not yield their peripheral speeds would exceed by a substantial amount the predetermined linear speed of the strands.

11. Apparatus for advancing a plurality of individual, paramagnetic strands simultaneously from individual supplies thereof along a tortuous path to individual take-up reels at a predetermined linear speed and under substantially constant, equal tensions, which comprises a common magnetic capstan for withdrawing said strands simultaneously from their respective supplies, means for rotating the magnetic capstan at a constant peripheral speed, magnetic means associated with the magnetic capstan and so designed as to magnetically hold each strand agairist the magnetic capstan with such force that the strands are advanced thereby without slippage of the strands on the magnetic capstan at a linear speed equal to the peripheral speed of the magnetic capstan, a segmented, strand-tensioning capstan including a rotatable drum, and a plurality of individual, annular, strand engaging sections arranged side-by-side on the drum in coaxial relationship therewith and normally frictionally engaged with the drum for rotation therewith, each of said sections being designed to yield rotationally relative to the drum when a predetermined torque applied thereto resulting from the frictional pull exerted thereon by its respective strand exceeds av predetermined value, means for rotating the drum at a constant predetermined speed such that the peripheral speed of the strand-engaging sections when there is no rotational yield relative to the drum exceeds substantially the predetermined linear speed of the strands, and drive means for driving the take-up reels so as to maintain substantially constant and equal tensions in the strands on the recess side of the segmented, strand-tensioning capstan.

12. Apparatus for advancing a plurality of individual, paramagnetic strands simultaneously from individual supplies thereof along a tortuous path to individual take-up reels at a predetermined linear speed and under substantially constant, equal tensions, which comprises a common magnetic capstan for withdrawing said strands simultaneously from their respective supplies, means for. rotating the magnetic capstan at a constant peripheral speed, magnetic means associated with the magnetic capstan and so designed as to magnetically hold each strand against the magnetic capstan with such force that the strands are advanced thereby without slippage of the strands on the magnetic capstan at a linear speed equal to the peripheral speed of the magnetic capstan, a segmented, strand-tensioning capstan including a rotatable drum, and a plurality of individual, annular, strand-engaging sections arranged side-by-side on the drum in coaxial relationship therewith and normally frictionally engaged with the drum for rotation therewith, each of said sections being designed to yield rotationally relative to the drum when a predetermined torque applied thereto resulting from the frictional pull exerted thereon by its respective strand exceeds a predetermined value, means for rotating the drum at a constant predetermined speed such that the peripheral speed of the strand-engaging sections when there is no rotational yield relative to the drum exceeds substantially the predetermined linear speed of the strands, means for driving the take-up reels in such a manner as to maintain substantially constant and equal tensions in the strands on the recess side of the segmented, strand-tensioning capstan, a plurality of grooved rollers positioned spacedly in series intermediate of the magnetic capstan and the strand-tensioning capstan, said strands being wrapped partly around each of the rollers, the angles of wrap of the strands on any one roller being substantially equal, and means for rotatably overdriving the rollers at peripheral speeds in excess of the fixed linear speed of the strands whereby each of the rollers exerts a frictional pull on each of the strands to contribute to the tensioning thereof.

1 No references cited. 

